Unusually High Gas-to-Dust Ratios Observed in High-Redshift Quiescent Galaxies

Understand

Tracking the cold molecular gas contents of galaxies is critical to understand the interplay between star formation and galaxy growth across cosmic time.

• Observations of the long-wavelength dust continuum, a proxy for the cold gas, are widely used in the high-redshift community because of their ease and efficiency.
• These measurements rely on the assumption of a molecular gas-to-dust mass ratio, typically taken to be GDR ~ 100 in massive, metal-rich systems.
• We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of the 870um dust continuum in a sample of five massive quiescent galaxies at z ~ 1 with existing detections of CO(2-1).